Code Change Summary: New requirements added to address GFCI and SPGFCI protection for horticultural lighting.

Section 410.184 was new in the 2020 NEC^® and required ground-fault circuit interrupter (GFCI) protection for outlets supplying lighting equipment identified for horticultural use employing a flexible cord with one or more “conductors”. The word “conductors” was supposed to be “connectors” but was mistakenly swapped during the second draft meetings when the code language was finalized.

Horticultural luminaires are often cord-connected and able to be tilted or aimed after installation.

Section 410.62(B) permits cord-connected luminaires that require adjusting or aiming after installation to be hard-wired without an attachment plug or cord connector. The 2020 NEC^® language in Section 410.184 was originally intended to require GFCI protection for those cord connected horticultural luminaires that had an attachment plug or connector.

In the 2023 NEC^®, Section 410.184 was revised to correct this error. Now, lighting equipment identified for horticultural use and employing a flexible cord with one or more separable connectors or attachment plugs must be supplied by lighting outlets protected by a listed GFCI.

A new exception was also added since some horticultural lighting is greater than 150 volts to ground such as 277-volt circuits. Typical Class A GFCI protection cannot be used on circuits exceeding 150 volts to ground. For circuits greater than 150 volts to ground, listed SPGFCI (Special Purpose Ground-Fault Circuit-Interrupter) is required.

A listed Class A GFCI device is for personnel protection and designed to trip when current leakage to ground is in the range of 4 mA to 6 mA.

Ground-Fault Protection of Equipment (GFPE) is for equipment protection and designed to trip in the 30 mA or higher range, and therefore not typically selected for personnel protection.

An SPGFCI is a device used in circuits with voltage to ground greater than 150 volts that detects ground-fault currents, and functions to de-energize a circuit when ground-fault current is detected that exceeds the values established for Class C, D, or E devices.

SPGFCI devices trip at higher levels of current leakage than a Class A device, but at lower levels than a GFPE device; typically, between 15mA and 20mA.

Below is a preview of the NEC^®. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2023 NEC^® edition of NFPA 70.